Jon Hunter bc8e157fdb mtd: core: Fix freeing of otp_info buffer
Commit 4b361cfa86 ("mtd: core: add OTP nvmem provider support") is
causing the following panic ...

 ------------[ cut here ]------------
 kernel BUG at /local/workdir/tegra/linux_next/kernel/mm/slab.c:2730!
 Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM
 Modules linked in:
 CPU: 3 PID: 1 Comm: swapper/0 Not tainted 5.13.0-rc2-next-20210518 #1
 Hardware name: NVIDIA Tegra SoC (Flattened Device Tree)
 PC is at ___cache_free+0x3f8/0x51c
 ...
 [<c029bb1c>] (___cache_free) from [<c029c658>] (kfree+0xac/0x1bc)
 [<c029c658>] (kfree) from [<c06da094>] (mtd_otp_size+0xc4/0x108)
 [<c06da094>] (mtd_otp_size) from [<c06dc864>] (mtd_device_parse_register+0xe4/0x2b4)
 [<c06dc864>] (mtd_device_parse_register) from [<c06e3ccc>] (spi_nor_probe+0x210/0x2c0)
 [<c06e3ccc>] (spi_nor_probe) from [<c06e9578>] (spi_probe+0x88/0xac)
 [<c06e9578>] (spi_probe) from [<c066891c>] (really_probe+0x214/0x3a4)
 [<c066891c>] (really_probe) from [<c0668b14>] (driver_probe_device+0x68/0xc0)
 [<c0668b14>] (driver_probe_device) from [<c0666cf8>] (bus_for_each_drv+0x5c/0xbc)
 [<c0666cf8>] (bus_for_each_drv) from [<c0668694>] (__device_attach+0xe4/0x150)
 [<c0668694>] (__device_attach) from [<c06679e0>] (bus_probe_device+0x84/0x8c)
 [<c06679e0>] (bus_probe_device) from [<c06657f8>] (device_add+0x48c/0x868)
 [<c06657f8>] (device_add) from [<c06eb784>] (spi_add_device+0xa0/0x168)
 [<c06eb784>] (spi_add_device) from [<c06ec9a8>] (spi_register_controller+0x8b8/0xb38)
 [<c06ec9a8>] (spi_register_controller) from [<c06ecc3c>] (devm_spi_register_controller+0x14/0x50)
 [<c06ecc3c>] (devm_spi_register_controller) from [<c06f0510>] (tegra_spi_probe+0x33c/0x450)
 [<c06f0510>] (tegra_spi_probe) from [<c066abec>] (platform_probe+0x5c/0xb8)
 [<c066abec>] (platform_probe) from [<c066891c>] (really_probe+0x214/0x3a4)
 [<c066891c>] (really_probe) from [<c0668b14>] (driver_probe_device+0x68/0xc0)
 [<c0668b14>] (driver_probe_device) from [<c0668e30>] (device_driver_attach+0x58/0x60)
 [<c0668e30>] (device_driver_attach) from [<c0668eb8>] (__driver_attach+0x80/0xc8)
 [<c0668eb8>] (__driver_attach) from [<c0666c48>] (bus_for_each_dev+0x78/0xb8)
 [<c0666c48>] (bus_for_each_dev) from [<c0667c44>] (bus_add_driver+0x164/0x1e8)
 [<c0667c44>] (bus_add_driver) from [<c066997c>] (driver_register+0x7c/0x114)
 [<c066997c>] (driver_register) from [<c010223c>] (do_one_initcall+0x50/0x2b0)
 [<c010223c>] (do_one_initcall) from [<c11011f0>] (kernel_init_freeable+0x1a8/0x1fc)
 [<c11011f0>] (kernel_init_freeable) from [<c0c09190>] (kernel_init+0x8/0x118)
 [<c0c09190>] (kernel_init) from [<c01001b0>] (ret_from_fork+0x14/0x24)
 ...
 ---[ end trace 0f652dd222de75d7 ]---

In the function mtd_otp_size() a buffer is allocated by calling
kmalloc() and a pointer to the buffer is stored in a variable 'info'.
The pointer 'info' may then be incremented depending on the length
returned from mtd_get_user/fact_prot_info(). If 'info' is incremented,
when kfree() is called to free the buffer the above panic occurs because
we are no longer passing the original address of the buffer allocated.
Fix this by indexing through the buffer allocated to avoid incrementing
the pointer.

Fixes: 4b361cfa86 ("mtd: core: add OTP nvmem provider support")
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Reviewed-by: Michael Walle <michael@walle.cc>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20210518185503.162787-1-jonathanh@nvidia.com
2021-05-26 10:39:27 +02:00
2021-05-07 00:26:34 -07:00
2021-05-07 00:26:35 -07:00
2021-05-09 14:17:44 -07:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
Description
No description provided
Readme 3.4 GiB
Languages
C 97%
Assembly 1%
Shell 0.6%
Rust 0.5%
Python 0.4%
Other 0.3%